When Johnson Controls began designing the next version of its Metasys Building Management System, it needed a technology platform with rich functionality, a highly productive tool set, and comprehensive support for Internet standards. Microsoft Windows XP Embedded and Microsoft .NET-connected technologies met the requirements, enabling the company to deliver a full-featured, easily integrated solution that can be accessed through a broad range of devices and applications.

In 1883, Professor Warren S. Johnson received a patent for the first electronic room thermostat. His invention launched the building control industry and was the impetus for the Johnson Electric Service Company-renamed Johnson Controls, Inc. in 1974. In 1978, the company expanded its focus on facility management and control to include automotive batteries, and, in 1985, to include automotive interiors. Today, Johnson Controls is a global leader in all three areas, with revenues of U.S.$20.1 billion for 2002-placing the company at #111 in the Fortune 500.

At Johnson Controls, roughly 30 percent of 112,000 employees work in the company's Controls Group, an industry leader in building automation systems and facility management solutions. The company's flagship Metasys® Building Management System is a combination of electronic components and software programs that automate a building's core systems, helping owners and managers of commercial, institutional, and government facilities worldwide to maximize comfort, productivity, safety, and energy efficiency. The Metasys system also collects historical data on the usage, behavior, and performance of these core systems, helping building operators to optimize equipment maintenance and make better decisions.

One of the key building blocks in most Metasys solutions is the supervisory controller, which monitors and orchestrates the actions of a building's various electrical and mechanical systems: heating, ventilation, air conditioning, lighting, access control, and fire safety. When Johnson Controls began designing the latest version of its Metasys system, there were several factors that influenced the company's decision on which technologies to use: Integration with other devices and systems. In addition to integrating with each other, Metasys system components need to connect with other systems and devices. "A large part of our business is services and integration, which often extends beyond our own products," says Hill. "For example, we may need to integrate with an airport departure/arrival system to control gate lighting. Similarly, data on energy usage needs to flow out of our controller and into another system so that airlines can be billed for the power that is used."

• Support for standard network protocols. Historically, components of building automation systems have relied on proprietary operating systems, communicating with each other using proprietary protocols. Although industry-specific standards for device communication (like the BACNET protocol) have recently emerged, many IT departments view these protocols and the devices that use them as proprietary. "Building automation systems and traditional IT environments are converging at a rapid pace, yet IT departments are hesitant to allow proprietary protocols or operating systems on their networks," says Dr. Byron Hill, Director of Systems and Technology Marketing at Johnson Controls. "Our products have to support those network standards and protocols that IT departments already know and trust."
• Accessibility through Internet technologies. Facility personnel and building engineers are rarely seated at a dedicated facility workstation. They need to access and act on information in building automation systems from any location and through the broadest possible range of devices. "To make the information in our systems more valuable, we need to make it more accessible and actionable," says Hill. "Customers want facilities solutions that are based on Internet technology-systems that they can access with Web browsers, smart client applications, and mobile devices."
• Scalability-from small buildings to large enterprises. Small buildings may need only one Metasys supervisory controller, whereas larger buildings may use dozens or hundreds of such devices that all need to communicate with each other. In larger installations, these devices also need to connect with Metasys software running on traditional Microsoft® Windows®-based workstations or servers-as a means of providing facility managers with centralized control, data capture, and reporting capabilities. "When we examined our options, we saw that XML Web services offered an ideal way to integrate the various components of our systems," says Dan Curtis, Engineering Manager at Johnson Controls.
• Integration with other devices and systems. In addition to integrating with each other, Metasys system components need to connect with other systems and devices. "A large part of our business is services and integration, which often extends beyond our own products," says Hill. "For example, we may need to integrate with an airport departure/arrival system to control gate lighting. Similarly, data on energy usage needs to flow out of our controller and into another system so that airlines can be billed for the power that is used."

Although Johnson Controls needed the Metasys system to support common Internet standards, it wanted to avoid the delays and expense associated with sourcing, evaluating, and integrating a number of third-party technologies-as it would need to do with a traditional embedded operating system. "In the past, we've tried to extend existing proprietary implementations to support Internet standards, but this resulted in increased development time and incompatibility with some of the many possible building network configurations," says Curtis.

In addition, Johnson Controls wanted to avoid developing the same software features twice. The previous version of the Metasys system used an internally developed operating system for the supervisory controller, while other software-based system components ran on desktop and server versions of the Microsoft Windows operating system. "Supervisory controllers and Metasys software solutions share a significant number of capabilities," says Curtis. "But because they used different operating systems, we were forced to develop many of the same features twice."

To address these challenges, Johnson Controls decided to build its new supervisory controller using Microsoft Windows XP Embedded, an embedded operating system that is based on the same binaries as Windows XP Professional and that facilitates the rapid development of reliable, flexible devices. Windows XP Embedded enabled Johnson Controls to select the specific Windows technologies it desired for the Metasys system and provided a rich set of development tools that facilitated the rapid development of an operating system image-one that supported the company's selected hardware and provided the exact user experience required.

"We looked at several other options including QNX, VxWorks, Linux, and our own in-house operating system," says Curtis. "Windows XP Embedded was the only solution that offered everything we needed in an integrated package: all networking and Internet protocols, a built-in Web server, support for Web services, and the Microsoft Data Engine for database functions. No other vendor can offer that."

Development tools were another factor in the company's decision. "Like all versions of Windows, Windows XP Embedded is supported by [Microsoft] Visual Studio® .NET, which meant that we could use the same development tools with which we were already familiar," says Curtis. "With Windows XP Embedded, code can be developed on the desktop and then copied to the target device. Other embedded platforms typically require multiple tools, which would have introduced a learning curve that we could not afford."

Choosing Windows and .NET-connected technologies gives Johnson Controls a single platform that can scale from the smallest devices to the largest of enterprise configurations: Windows CE .NET for smaller embedded devices, Windows XP Embedded for larger controllers, Windows XP Professional for PC-based solutions, and Microsoft Windows Server? 2003 operating system for server-class installations. Johnson Controls is now able to write code once and reuse it across multiple components of the Metasys product line. "Microsoft is the only vendor that has a complete story from the smallest embedded devices to the largest enterprise configurations," says Curtis. "We can now share code across all devices that make up a building automation system."

By exposing the functionality in Metasys system components using Web services, Johnson Controls ensures that its solutions are accessible by the broadest possible range of external systems and devices, and through protocols that are widely accepted in today's IT environments. For the first release of the company's new Metasys system, developers focused on two types of Web services:By exposing the functionality in Metasys system components using Web services, Johnson Controls ensures that its solutions are accessible by the broadest possible range of external systems and devices, and through protocols that are widely accepted in today's IT environments. For the first release of the company's new Metasys system, developers focused on two types of Web services: those that are used between Metasys controllers, workstations, and servers; and those that interact with the company's browser-based Java applet, which provides a user interface into the building management system. Over the next few months, developers will augment these Web services with additional ones targeted at third-party developers.

"We chose Web services because they're based on widely accepted Internet standards like HTTP, XML, and SOAP," says Curtis. "As such, they use the same protocols that already exist on a network, work well with firewalls and over the Internet, and enable integration at the device, system, and IT levels. And we chose Windows XP Embedded and Microsoft .NET-connected technologies because together they offered the cleanest and fastest way to build Web services into our solution. With other embedded platforms, we would have needed to add a layer on top of the operating system, at significant additional time and expense. Microsoft is the only vendor with an integrated platform for implementing Web services in an embedded solution."

Latest Enhancements to Increase Developer Productivity Johnson Controls initially began development with Windows XP Embedded but switched to Windows XP Embedded with Service Pack 1 (SP1) when it became available. This updated version offered a componentized version of the Microsoft .NET Framework-an integral Windows component that supports building and running the next generation of Windows-based applications and Web services. This enhancement saved developers significant time when creating a new system image. "Prior to Windows XP Embedded with SP1, we had to integrate the Framework into the operating system image manually," says Nick Schaf, Software Engineer at Johnson Controls. "Having the Framework included in the updated version shaved three steps and two hours off the time it took to build an image."

Another advantage of switching to the updated version was its inclusion of the Footprint Estimator. A new feature in the Windows Embedded Studio development tool set, which is included in Windows XP Embedded with SP1, the Footprint Estimator enables developers to estimate the footprint size of individual components and their dependencies (as well as macro components) without adding them to an image first. "With the Footprint Estimator, I don't need to go through the entire build process to see what effect a new component will have on image size," says Schaf. "I can just choose a component in the component browser, right-click, and select Estimate Footprint."

The software in the Metasys supervisory controller was developed by a team of 12 developers over a period of 18 months using Visual Studio .NET development system and the C# development language. The headless device has 256 megabytes (MB) of RAM and 256 MB of CompactFlash memory, of which 170 MB is used by the operating system image. The supervisory controller's processor is a National Geode GX1 CPU running at 300 MHz. The device has 10/100 Mbps Ethernet connectivity as well as support for an optional internal or external modem. Its two RS-485 field bus trunks can accommodate up to 2,000 input/output parameters.

With Microsoft Windows XP Embedded and .NET technologies, Johnson Controls built a solution that uses Web services to expose the extensive facility management expertise built into Metasys. While Hill believes that taking this approach will help to increase acceptance of Metasys solutions in traditional IT environments, he points out that the company's primary motivation for taking this path is to deliver increased customer value.

"Any building automation system can collect raw facilities data," says Hill. "By using Microsoft .NET to expose the capabilities of the Metasys system through Web services, we're giving building operators access to facilities information-and an ability to act on it-at levels they've never had before. As a result, they can run their buildings the way they want instead of how technology limits mandate. And as building automation systems and IT continues to converge, we'll have a solution that both facilities staff and IT personnel are comfortable with. More important, we are now even better positioned to address customer requests for new features, services, or integration points."

According to Curtis, the decision to use Windows XP Embedded and .NET technologies enabled his team to deliver the new version of Metasys more than twice as fast as before. "Developing a system of this complexity would have taken four years on any other platform," he says. "Windows XP Embedded, the Microsoft .NET Framework, and Visual Studio .NET enabled us to deliver a complete solution in only 18 months.

"Windows XP Embedded gave us all the technologies and components we needed in a single package, already tested together and ready to use. Visual Studio .NET significantly enhanced developer productivity, giving us an integrated development environment for the entire project. The wealth of prebuilt plumbing in the Framework minimized the amount of code to write, allowing us to deliver more functionality in a given amount of time. Finally, we didn't need to develop functionality twice for different classes of devices. Ninety percent of the code running in a Metasys workstation or server is the same as what's in a supervisory controller."

With its built-in Web server, a Metasys supervisory controller now can exist as a stand-alone device in a small building-without the need for a dedicated operator workstation or physically connecting a laptop to the controller to query the system or input changes. Facility personnel can access the controller from any Web browser connected to the building's LAN-or from any remote location with Internet access if firewall permissions are set accordingly.

"In the past, a building engineer might have needed to physically drive to a facility to troubleshoot a situation," says Hill. "With the support for Web services and Web-based standards like HTTP built into the Metasys platform, the same engineer can now access a building system from any location with a Web browser. For Johnson Controls and its customers, Microsoft .NET has delivered on its promise: connecting people, information, systems, and devices-anyplace and at any time."

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